Does anybody no if 3,5-diiodo-L-thryonine or T2 is the same as diodothyronine?

I cant find this in either my chemistry or exercise physiology book. Triiodothyronine is known as T3. My deductive guess is that it is T2. The 3,5 tells the position of the iodine and di means that there are two.

Thanks for the reply.